Paris to Caen via Gare-Saint Lazare station question??

Take the RER B from the airport to Paris Nord.

At Gare du Nord, use the tunnel to the Magenta station.

Catch the RER E to Haussman-St-Lazare.

Use another tunnel to walk to the St Lazare train station.

To answer your train booking question: you will be able to buy tickets at the station but you can get significantly discounted fares if you book in advance (tickets usually go on sale ninety days before). Book tickets online at www.tgv-europe.com, claim to live in the UK, and ask to pick up your booked tickets at the station. (If you tell the site you live in the USA you'll be sent to raileurope.com, which is designed to hard-sell expensive rail passes to naive Americans whether or not they need one.)

Note however that the advance cheap fares are strictly tied to a single journey and you lose out if you miss that train, which may cause problems since you're flying in that same day and flights can be delayed.

Steve - you don't mention how many travelers there are. I assume coming from Monee you are outbound out of O'Hare (we live in Northbrook). That being said, when you get to CDG, get the luggage, etc. you are going to be quite tired. We tried to do the train into Paris last summer but we had three tired kids so we took a cab. It was money well spent. I would also say that you are pressing on to Bayeux that same day of arrival you may want the time to chill out in the cab.

BYW - we went to Bayeux. I looked at rental cars and wound up just taking the train to Bayeux, walking to the hotel (it's not far into town) and then hiring a guide to do all the WWII sites. The guide hired the car for us - we paid her. Much less hassle than the car looked although the benefit of the car is that you can go around the countryside if you want.

As far as Gare-St. Lazare, we wound up using Eurorail tix that I bought here. Yes, probably a little more expensive than at the station, but I had them in my hand when we arrived and was glad I did as the line at the station was long. We had second class reserved seats. If it were just me and my husband I probably would have just used the kiosk there. Another perk, the tix were sent from Rosemont, IL and there was a live person I could call if things went awry.

Have fun.

Currently you can buy Prems tickets for October first to Caen for 15 euro. Full price fares are 32 euro.

You'll have to decide if a savings of 12 euro is worth either the chance of you missing your train and having to buy a new full fare ticket, or giving yourself too much time and having to wait around the Gare for a few hours. (St. Lazare was my second home in 2008, theres not a lot to see while waiting for a train)

Either way trains to Caen, as well as the ticket office are at the far right hand side of the station.

You need to allow up to an hour to claim your luggage and clear immigration/passport control. Allow a little under an hour to get from CDG to Gare Saint-Lazare. If your plane is on time, you have a chance of catching the 12:10 train to Caen. If you book a Prem's fare ticket which is non-refundable and non-exchangeable, then make it for the 14:10 train. Book at www.tgv-europe.com. To keep the site in English and to avoid being bumped to the Rail Europe site which doesn't offer discount fares, choose Great Britain as your country of residence.

There's only 2 of us traveling and wer'e packing light by bringing carry on's only. Another option is to rent a car at the airport and drive from Bayeux direct. The reason I'd like a car is to be able to drive to Mt Saint Michel and not worry about how long we can stay plus see some countryside. Thanks all for the great advice. The taxi idea from the airport to Gare Saint lazare sounds good too. Anyone know what that might cost compared to the train?

If you're up to it after the flight, you can drive to Bayeux in three hours, plus stops, from CDG at mid day.
Have cash for tolls -- probably twenty-five euros. Some say credit cards will work, but I've never been willing to count on it.

A taxi from CDG to Gare Saint-Lazare will cost around €50. The RER costs €8.70/person.